This invention relates to new and improved well bore apparatus which is cooperatively arranged to be dependently suspended in a well bore from a pipe string and selectively operated for injecting treating fluids into one or more earth formations. More particularly, the present invention involves a new and improved fluid-treating tool including full-bore valve means comprised of upper and lower members which are telescoped together and adapted for cooperatively receiving a retrievable valve member having upper and lower valve elements adapted to be alternatively seated on upper and lower valve seats in response to movement of the telescoped members between spaced operating positions for selectively controlling the injection of treating fluids from discharge ports located between spaced packer means cooperatively arranged around the lower member for isolating a selected well bore interval that is being treated.